Automatic distilling system

ABSTRACT

An automatically controlled distilling system is provided for use with a machine employed in the solvent scouring of textile materials. The system includes a plurality of interconnected stills each with its own condenser and water separator through which dirty solvent discharged from the scouring machine is distilled in order to return clean solvent back to the machine. Automatically actuated valves and pumps for directing and transferring solvent, sludge and steam through the system are controlled by timers responsive to certain pre-set conditions and adapted to cycle the stills in staggered sequence.

Wilcox United States Patent [1 1 Oct. 28, 1975 [73] Assignee: Riggs &Lombard, lnc., Lowell,

[22] Filed:

Mass.

Mar. 18, 1974 211 Appl. No.: 452,216

[52] US. Cl 202/160; 613/18 R, 68/18 C; 202/172; 202/206; 202/174;202/169; 203/2;

[51] Int 210/138; 159/17 Cl. B011) 3/42; B01D 3/02 [58] Field of Search202/160, 172, 173, 206, 202/155, 156, DIG. 7, DIG. 18; 203/1, 2, 71',

159/17 P, 20', 68/18 R, 18 C; 210/138 References Cited UNITED STATESPATENTS 12/1938 Hetzer 202/181 11/1939 Hinckley 159/20 R 11/1941 Talton159/20 R 3,366,551 l/1968 Kaso 210/138 X 3,503,433 3/1970 Riva et a1159/24 R Primary ExaminerNorman Yudkoff Assistant ExaminerD. SandersAttorney, Agent, or FirmMorse, Altman, Oates & Bello [5 7 ABSTRACT Anautomatically controlled distilling system is provided for use with amachine employed in the solvent scouring of textile materials. Thesystem includes a plurality of interconnected stills each with its owncondenser and water separator through which dirty solvent dischargedfrom the scouring machine is distilled in order to return clean solventback to the machine. Automatically actuated valves and pumps fordirecting and transferring solvent, sludge and steam through the systemare controlled by timers responsive to certain pre-set conditions andadapted to cycle the stills in staggered sequence.

4 Claims, 2 Drawing Figures VENT "I *2 *3 22 TIMER TIMER TIMER 72 o o oo o o E O O 0 H P O o 0 an: 4

1] A II o 10 I4 as 58 l D STEAM STEAM u 12 v o o o DIRTY SOLVENT 46RECEIVING s4 TANK 4 JI M2 22 US. Patent Oct. 28, 1975 Sheet 1 of23,915,808

WIIO o o $2; $2; $2; mm Q Q AUTOMATIC DISTILLING SYSTEM BACKGROUND OFTHE INVENTION 1. Field of the Invention This invention relates generallyto distilling systems and more particularly is directed towards anautomatic distilling system operatively connected to a machine used forthe solvent scouring of textile materials.

2. Description of the Prior Art In the production of various types oftextile materials it is common practice to clean the material at leastonce during its production in order to remove various impurities. Oneimpurity in particular is oil which quite often is intentionally addedto the fibers in order to reduce friction. The oil, of course, must beremoved after the web has been formed, as by weaving or knitting, inorder that other processes may be carried out on the web such as dyeing,printing or the like. A common method for removing the oil and otherimpurities is to subject the web to a scouring process in which a drycleaning solvent is employed by spraying the solvent against the web orbathing the web in a tank containing the solvent. By whatever means thesolvent is applied to the web, the dirty solvent normally is recoveredand distilled for re-use. Distillation systems of this type heretoforeprimarily have involved single stills and condensers and these generallyhave been manually operated.

It is an object of the present invention to provide a new and improveddistilling system for use with solvent scouring machines. Another objectof the invention is to provide an automated distilling system forsolvent scouring machines having a high operating capacity and adaptedto convert dirty solvent to clean solvent on a highly efficient basis.

SUMMARY OF THE INVENTION This invention features an automaticdistillation system for use with a machine employed in solvent scouringtextiles, comprising a plurality of stills, a condenser operativelyconnected to each still, a water separator operatively connected to eachcondenser, separate tanks for temporarily storing dirty solvent andclean solvent, automatically and remotely operated pumps and valvesprovided in conduits interconnecting the stills, condensers, separatorsand tanks and a timing control unit operatively connected to the pumpsand valves for operating the stills, valves and pumps in a predeterminedsequence according to predetermined conditions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of adistilling system made according to the invention, and,

FIG. 2 is a schematic circuit diagram employed in the FIG. 1 system foroperating the various components.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 1 Referring now to thedrawings and to FIG. 1 in particular, the reference character generallyindicates a solvent scouring machine of the sort shown in US. Pat. Nos.3,701,269, 3,643,475 or 3,640,090 wherein a running web 12 is scoured asby jets 14 of a solvent sprayed over the face of the web. In addition tothe jets of solvent, a tank of solvent may be employed in which the webis carried in and out to enhance the cleansing action. Various types ofcommercially available solvents may be employed. In any event, the web12 typically might contain 5% oil and running at a rate of 35 yards perminute may result in the removal of perhaps 10 gallons of oil an hour.The oil removed from the-web by the scouring action is mixed in with thesolvent and this dirty solvent is removed from the scouring machine 10through a conduit 16 to a dirty solvent receiving tank 18. The receivingtank 18 is provided with a pressure switch 20 and a conduit 22 connectedto a transfer pump 24 which, in turn, is connected by means of a conduit26 to a dirty solvent tank 28, typically having solvent tank 28 isconnected by conduits 30 and 32 to still No. 1 and still No. 2, both ofthese stills typically being of 800 gallons capacity per hour. StillsNo. I and 2 are employed for regular distilling and both are con-.

nected by a conduit 34 to a relatively small clean solvent storage tank36, typically of gallons capacity. The tank 36 is adapted to deliverclean solvent to either still No. 1 or still No. 2 in case ofcontamination.

Still No. 3 is connected to the drain lines 38 and 40, respectively, ofstills Nos. 1 and 2, the drain lines feeding to a common transfer pump42 discharging through a conduit 44 to still No. 3. The No. 3 still isused primarily to carry out a boiling off process whereby accumulatedoils are periodically stripped. The No. 3 still is supplied from eitherstill No. l or 2 by means of'the transfer pump 42, typically having acapacity of 50 gallons per minute. No. 3 still is connected by means ofa conduit 46 to a sludge pump 48, typically a gear-type pump having acapacity of 28 gallons per minute, for removing sludge and oil to awaste receptacle. 7

Nos. 1 and 2 stills are provided with three pressure switches 50, 52 and54 serving respectively as a high pressure switch, alow. pressure switchand a medium pressure switch. No. 3 still is equipped with only a highpressure switch 51 and a low pressure switch 53. These pressure switchesmaintain the level of the liquid within each still. The function of theswitches will be described more fully below during the description ofthe operation of the system. Also, each of the stills is equipped withsteam heating coils appropriately valved for heating the solvent todistillation temperatures.

Each of the stills is connected by a trunk 56, 58 and 60 to anassociated condenser 1, 2 and 3, respectively, wherein the solvent vaporfrom the stills is condensed back into liquid form. The condensate fromeach of the condensers first passes through an associated solvent cooler62, 64 and 66, respectively, and thence through water separators l, 2and 3, respectively.

Nos. 1 and 2 water separators receive clean solvent from coolers 62 and64, respectively, and discharge to the clean solvent storage tank 36through conduits 68 and 70, respectively. Water separators Nos. 1 and 2are provided with thermostats 72 and 74, respectively, and these areadapted to shut off steam to the related still if the condensate getstoo hot. The thermostat is also adapted to stop delivery of the solventfeed to the stills in such event. The No. 3 water separator receivessolvent from the No. 3 cooler and discharges its condensed solvent tothe dirty solvent tank 28 through a conduit 76. The three waterseparators pass any separated water to a common drain pipe 78. Also, ineach of the three stills there is provided a separate valved drainconnecting to a common drain pipe. These drains from the three stillsare used when the heating coils within the stills are periodicallycleaned as by boiling them with water and caustic soda.

Drain connections are furnished on each of the three coolers and thethree water separators and all feed through still No. 3 for use if anyof them should be contaminated. In practice, the liquor level sensors inthe stills typically are set to function at different levels of liquid.For example, the high pressure switch 50 is adapted to maintain acontrolling level of solvent be tween 21 and 24 inches, approximately,the medium pressure switch 54 is adapted to maintain a liquor level ofapproximately 16 inches and the low switch 52 functions at about 1 inchof liquor level. These levels can, of course, be changed according toparticular systems.

The clean solvent collected in the tank 36 overflows through a conduit78 to a relatively large clean solvent tank 80, typically ofa 1,000gallons capacity. From the tank 80 clean solvent is returned to thescouring machine by means of a clean solvent pump 82 delivering througha conduit 84, through a meter 86, typically set at 25 gallons perminute, and thence through spray bars 88 and 90 where it is sprayed ontothe web 12 in jets 14.

The system is controlled by selective operation of the various pumps andby means of solenoid actuated valves, labeled S1 through S8, and thefunction will be described in connection with the operation of thesystem.

The operation of the pump and valves is under the control of a timingunit 92 provided with three timers, timer No. 1, timer No.2 and timerNo.3 adapted to operate, respectively, stills Nos. 1, 2 and 3. The unitis also provided with indicator lights and switches to be described inconnection with the operation of the system.

In operating a system having capacities suggested in the illustratedembodiment it is preferable that the quantity of solvent in the systemat any one time be kept below 1,000 gallons. Obviously, this figure maybe changed depending upon the size of the particular system. In theillustrated system, however, the rate of distillation is not controlledto the rate of clean solvent feed. For example, if the rate of cleansolvent feed is less than the rate of distillation, the clean solvent1,000 gallon storage tank 80 would gradually approach capacity while thedirty solvent tank 28 would become empty.

The illustrated distillation system employs three 20 hour timers 1, 2and 3, one for each still. In the initial startup of the system, timerNo. 2 is delayed until timer No. 1 is halfway through its cycle ofoperation of still N0. 1. Thereafter, still No. 2 will always be halfout of phase of still No. 1 unless the distillation time is changed.

By way of example, in setting up the time period for distillation, atypical installation for fabric containing 5% oil weighing 12 ounces peryard and running at 35 yards per minute would accumulate 10 gallons ofoil per hour in stills No. 1 and No. 2. Therefore, an 18 hourdistillation rate is selected with a 1 hour dwell time. This means thateach of stills Nos. 1 and 2 will dump to still No. 3 every 18 hours ofmachine running time.

In describing the operation of the system, reference is limited to stillNo. l insofar as still No. 2 will perform a duplicate cycle except thatit will be half out of phase on time with still No. 1. Both timers Nos.1 and 2 are functional only when the clean solvent pump 82 is operatingsince that is the only time that oil accumulates. This is done throughnormally open contacts for a clean solvent feed pump starter. When thedistilling cycle starts, relay R1 (FIG. 2) is energized and solventflows either by gravity, as shown, or by pump, to No. 1 still from thedirty solvent tank 28 with valve S2 being open. As the liquor levelbuilds up in the No. 1 still, it will gradually reach a height ofperhaps 16 inches in a typical embodiment, which level will just coverthe heating coils in the still. Under these conditions, the mediumpressure switch 64 will close to energize relay R4 which, in turn, willopen steam valve S3. Solvent will keep on flowing into No. 1 still untilit reaches a height of approximately 24 inches which will re-act on thehigh pressure switch 50 causing it to close feed valve S2. This valvewill continue to open and close between liquor levels of 21 to 24 inchesfor the duration of the distillation period.

At this time relay R1 will be energized and this, in turn, willde-energize the relay for valve S2 causing it to close and stop the flowof solvent to still No. 1. Relay R6 is then energized to close thecircuit on the transfer pump 42. However, the transfer pump 42 cannot been ergized insofar as the contacts for relay R4 are still open. In thesame manner the drain valve 81 remains closed insofar as its relaycontacts are still open and sol vent will continue to be distilledalthough the solvent feed has stopped. Distillation will continue untilit reaches a level of approximately 16 inches in still No. 1. At thispoint, relay R4 is de-energized, closing the contacts which will openthe drain valve S1 and start the transfer pump 42. The discharge ofstill No. 1 is thereupon transferred to still No. 3 through the conduit44. The liquor level in still No. 1 will drop until it causes the lowpressure switch 52 to open, thereby deenergizing relay R8. This willstop the transfer pump 42 and close the drain valve S1. The system willremain in this state until the dwell time expires on timer No. l. Thetimer No. 1 will then switch to the distillation time period and repeatthe process.

Reference is now made to still No. 3 which performs the boiling offoperation. When the drains are pumped from the No. 1 still, the liquorlevel will start to rise in still No. 3. In still No. 3 its low pressureswitch will first close energizing relay R10 to start timer No. 3 whichtypically is set for 2 hours of boil off time. It will also closecontacts to relay R10 for drain valve S8 from No. 3 still, but the relayR3 contacts for the drain valve S8 are still open and valve S7 closesfurnishing steam to the coils for still No. 3.

At the expiration of the boiling off time for still No. 3 (typically 2hours) the contacts on timer No. 3 will switch to a dwell time ofapproximately 30 minutes to 1 hour setting. This will close steam valveS7 and energize relay R3. The closed contacts of relay R3 will keep themotor running on timer No. 3 and cause the sole noid actuated drainvalve S8 for still No. 3 to open and at the same time starting thesludge pump 48 which pumps the sludge from still No. 3 to a wastereceptacle. When the sludge in still No. 3 reaches a level ofapproximately 1 inch its low pressure switch will open causing the drainvalve S8 for still No. 3 to close and stop the sludge pump 48. At theexpiration of the dwell time period the contacts for timer No. 3 willswitch to deenergize the relay R3 and stop the motor for timer No. 3.Still No. 3 will then be ready for the next boil off operation whichnormally would then be from still No. 2.

In practice, the still No. 3 will accumulate sludge through severalcycles of distillation before the sludge pump is operated since the rateof accumulation of sludge in still No. 3 is relatively slow. Sludge ispumped out of No. 3 still only during a dwell period and not during theboiling off period.

By cycling stills Nos. 1 and 2 in staggered half out of phase sequenceboth drains may be dumped sequentially to still No. 3 without exceedingthe capacity of still No. 3.

Having thus described the invention, what I claim and desire to obtainby Letters Patent of the United States is:

1. An automatic system for recovering, distilling and returning solventsand the'like from and to a textile scouring apparatus, comprising a. adirty solvent storing tank adapted to receive dirty solvent from saidapparatus,

b. first, second and third stills,

c. first conduit means connecting said tank to each of said first andsecond stills,

d. second conduit means connecting said first and second stills to saidthird still,

e. a condenser operatively connected to each of said stills,

f. remotely controlled pump means in said second conduit means forselectively transferring residue liquid from said first and secondstills to said third still,

g. remotely controlled valve means connected to said first and secondconduit means,

h. timing means operatively connected to said valve means and said pumpfor operating said stills in predetermined timed sequence andalternately transferring residue liquid from said first and secondstills to said third still,

i. said timing means including a clock operatively connected to each ofsaid stills, each of said clocks adapted to operate its associate stillfor a predetermined period of time, the operating time period of theclock associated with the first still being substantially out of phasewith the operating time period of the clock associated with the secondstill,

j. liquid level sensing means mounted in each of said stills, saidsensing means being operatively connected to said pump means to saidvalve means,

k. a clean solvent storage tank connected to said condensers to receiveclean condensed solvent therefrom and second pump means connected tosaid clean solvent storage tank and to said apparatus for returningclean solvent to said apparatus, and,

L. a sludge pump connected to said third still for removing sludgetherefrom.

2. An automatic system according to claim 1 including remotely operatedheating means connected to each of said stills and to said timing means.

3. An automatic system according to claim 2 wherein said heating meansincludes third conduit means connected to a steam source and remotelycontrolled valve means connected to said third conduit means and to saidtiming means.

4. An automatic system according to claim 1 including water separatingmeans operatively connected to each of said condensers.

l l l

1. AN AUTOMATIC SYSTEM FOR RECOVERING, DISTILLING AND RETURNING SOLVENTSAND THE LIKE FROM AND TO TEXTILE SCOURING APPARATUS, COMPRISING
 2. Anautomatic system according to claim 1 including remotely operatedheating means connected to each of said stills and to said timing means.3. An automatic system according to claim 2 wherein said heating meansincludes third conduit means connected to a steam source and remotelycontrolled valve means connected to said third conduit means and to saidtiming means.
 4. An automatic system according to claim 1 includingwater separating means operatively connected to each of said condensers.